Phase current sensor fault-tolerant technique using information of DC side current in two-level inverter

The information of three-phase currents are very important for motor control. Some three-phase current reconstruction techniques were used in conventional two-level inverters using single DC current sensor for the purpose of cost reduction and sensor fault-tolerance. However, the validity would be affected because of planar bus bar and capacitor. A DC-link current sensor measures the sum of capacitor current and phase current. In this paper, a mathematical model is built and the parameters are recognized when the system is running. If the phase current sensor failure occurs, the state observer will be used to calculate the phase current.